U.S. patent application number 17/274987 was filed with the patent office on 2022-02-24 for an internal support system for cushions, mattresses and the like.
The applicant listed for this patent is Kumar Rajaratnam. Invention is credited to Kumar Rajaratnam.
Application Number | 20220053944 17/274987 |
Document ID | / |
Family ID | 1000005987258 |
Filed Date | 2022-02-24 |
United States Patent
Application |
20220053944 |
Kind Code |
A1 |
Rajaratnam; Kumar |
February 24, 2022 |
AN INTERNAL SUPPORT SYSTEM FOR CUSHIONS, MATTRESSES AND THE
LIKE
Abstract
An internal support system for a cushion, mattress or the like,
for supporting the body of a user, the internal support system
including: a main portion having a body facing side that
substantially opposes a base side; and a support portion located at
least partly within the main portion, the support portion including
a core portion and at least one peripheral portion which extends
laterally from the core portion, wherein the height of the core
portion is greater than the height of the at least one peripheral
portion, the height being that as determined in the direction from
the base side to the body facing side of the main portion, wherein
the support portion is more resistant to deformation than the main
portion.
Inventors: |
Rajaratnam; Kumar;
(Ewingsdale, AU) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Rajaratnam; Kumar |
Ewingsdale |
|
AU |
|
|
Family ID: |
1000005987258 |
Appl. No.: |
17/274987 |
Filed: |
June 27, 2019 |
PCT Filed: |
June 27, 2019 |
PCT NO: |
PCT/AU2019/050674 |
371 Date: |
March 10, 2021 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A47C 27/16 20130101;
A47C 27/148 20130101 |
International
Class: |
A47C 27/16 20060101
A47C027/16; A47C 27/14 20060101 A47C027/14 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 12, 2018 |
AU |
2018903422 |
Claims
1. A seat cushion for an office chair or the like, the seat cushion
including: a main portion having a front, rear, and lateral sides;
and a support portion at least partly within the main portion such
that it is centrally located between the lateral sides of the main
portion, the support portion being more resistant to deformation
than the main portion and including: a core portion of
substantially uniform vertical thickness that is centrally located
between the lateral sides of the main portion and which extends
towards the lateral sides of the main portion to a width for
supporting the ischial tuberosities of a user; and lateral
peripheral portions which extend laterally from the core portion
toward the lateral sides of the main portion, the peripheral
portions having lesser vertical thickness than the core portion so
as to provide a different support profile in the seat cushion when
compared to core portion.
2. A seat cushion as claimed in claim 1, wherein the peripheral
portions taper in vertical thickness from the core portion in the
direction toward the lateral sides of the main portion.
3. A seat cushion as claimed in claim 2, wherein the support
portion further includes a forward peripheral portion which extends
forwardly from the core portion toward the front side of the main
portion, the forward peripheral portion tapering in vertical
thickness from the core portion in the direction toward the front
side of the main portion.
4. A seat cushion as claimed in claim 3, wherein the forward
peripheral portion and the lateral peripheral portions taper
respectively to front and lateral ends of the support portion, the
front end extending between and substantially orthogonal to the
lateral ends, which are substantially parallel to one another.
5. A seat cushion as claimed in claim 1, wherein the core portion
has front, rear and lateral peripheries, the front periphery of the
core portion extending between and substantially orthogonal to the
lateral peripheries, which are substantially parallel to one
another.
6. A seat cushion as claimed in claim 1, wherein the support
portion is removably located within a recess in the main portion,
the recess configured to fit the support portion.
7. A seat cushion as claimed in claim 6, wherein the support
portion is slidingly received into the recess through an opening in
the rear side of the main portion.
8. A seat cushion as claimed in claim 3, wherein the support
portion includes a top surface and a base surface substantially
parallel thereto, the top surface having a greater area than the
base surface such that it extends beyond the base surface at the
forward and lateral peripheral portions, and, at each of the
forward and lateral peripheral portions, a sloping wall extends
from the base surface to meet the top surface.
9. A seat cushion as claimed in claim 8, wherein the sloping wall
at the forward peripheral portion slopes at a steeper angle to meet
the top surface than the sloping walls at the lateral peripheral
portions.
10. A seat cushion as claimed in claim 1, wherein the support
portion has a substantially trapezoidal cross section in the plane
traverse to a direction from the rear to the front of the main
portion.
11. A seat cushion as claimed in claim 1, wherein the main portion
is formed of a first foam material and the support portion is
formed of a second foam material.
12. An office chair including a seat cushion as claimed in claim 1.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to an internal support system
for cushions, mattresses and the like, for supporting the body of a
user, as well as to cushions, mattresses and the like,
incorporating same.
BACKGROUND
[0002] Internal/integral support systems for cushions, mattresses
and the like, for supporting the body of a user, vary widely. For
example, there are various known arrangements and constructions of
seat cushions. Traditional foam cushions for seats are typically a
foam cushion block which may be of one foam material. FIG. 1 is a
side sectional view of a prior art foam cushion block 110. Such
foam cushion seats may be sculptured with a concave upper surface
112 to provide comfort and a pleasing appearance. Other foam
cushion seats may have a further sculptured upper surface that
approximates a shape of the buttocks and a back of the thighs of a
seat user.
[0003] FIG. 2 is the prior art foam cushion 110 of FIG. 1 being sat
upon by a seat user 210. A compression to the foam cushion 110 is
applied by the user's 210 buttocks 212. The buttocks 212 soft
tissues include the gluteal muscles and fat about the pelvic bones
214, ischial tuberosities (sitting bones) 216, and trochanters
(femur heads) 218 of the skeleton. From the skeletal anatomical
features the principle compression force is applied by the ischial
tuberosities 216 in the direction of the arrows 220. In addition
the trochanters also apply a compression in the direction of the
arrows 222. When sitting for prolonged periods and/or on a seat
with inadequate cushioning, it is usually firstly about the ischial
tuberosities 216 and then the trochanters 218 that discomfort may
be felt. In particular the higher localised pressures applied by
the protruding sitting bones 216 may provide discomfort and pain in
the buttocks 212. This is particularly problematic for heavier
users using thinner and/or softer cushions. In such situations the
ischial tuberosities 216 are likely to "bottom out" to the harder
base structure of the seat.
[0004] FIG. 3 is a side sectional schematic of a prior art foam and
spring seat 310 being sat upon by a user 210. Foam and spring seats
310 are derived from prior art bedding spring. Typically the seat
310 may have a spring base 312 overlaid with a suitable cushion pad
314. A frame 316 may be used to support the spring base 312 and
cushion pad 314. Bedding spring technology typically does not
translate well to seats as the higher localised pressures applied
by the ischial tuberosities 216 compared with a prone body upon a
bed often result in the elements of the spring base 312 being felt
in the buttocks 212. Bedding springs also provide localised counter
pressure, even when joined together, and dissipate pressure
unevenly. This results in poor pressure distribution.
[0005] FIG. 4 is a side sectional schematic of a prior art webbing
based seat 410 also being sat upon by a user 210. The seat 410 may
have webbing or strap lattice work base 412 suspended by and
secured to a frame 316. A suitable cushion pad 314 may overlay the
webbing base 412. Such seats may also be derived from prior art
beds. The lack of base support directly under the buttocks 212 may
result in the seat base sagging into the frame 316 and consequently
the sides of the cushion pad 314 and webbing base 412 applying a
sideways force into the sides of the buttocks 212 as shown by the
arrows 414. Such a sideways force 414 from lack of base support can
give a restrictive feeling to the seat as well as applying an
uncomfortable pressure to or adjacent the trochanters 218.
[0006] A similar issue with the uncomfortable sideways force 414 to
the buttocks may apply to soft and thick seat cushions which
attempt to overcome the issue to bottoming out of the ischial
tuberosities by providing more cushioning as softer and deeper
cushions. Alternatively or in addition they may use gel pad/s
across the buttocks. However these approaches may commonly result
in the buttocks also sinking deeper into the softer cushion and the
consequent application of the uncomfortable and restrictive
sideways force 414 to the buttocks 212.
[0007] None of these prior art seating apparatus provides an
entirely satisfactory solution to the provision of comfortable
prolonged seating, nor to the ease of applying the seat cushion to
a wide range of the seating population.
[0008] The present invention seeks to address the above mentioned
disadvantages with existing seat cushions, as well as related
issues with mattresses and the like, for supporting the body of a
user.
SUMMARY OF THE INVENTION
[0009] In one broad form, the present invention provides a seat
cushion comprising: a first cushion of a first foam material; a
second cushion of a second foam material, the second cushion being
substantially contained within the first cushion; a base of the
second cushion substantially corresponds to a common base of the
first cushion; a top surface of the second cushion underlays an
upper layer of the first cushion; wherein the second cushion has a
top surface with an area greater than an area of the base of the
second cushion to form a peripheral region of the second cushion
that overlays a lower portion of the first cushion.
[0010] In one form, a stiffness of the first foam material is less
than a stiffness of the second foam material.
[0011] In one form, the peripheral region is adjacent to a seat
cushion user's trochanters and the base of the second cushion is
adjacent to the ischial tuberosities of the seat cushion
user's.
[0012] In one form, a span across the top surface substantially
corresponds to a span across a seat cushion user's trochanters. The
seat cushion, wherein a span across the base of the second cushion
is derived from a span across a seat cushion user's ischial
tuberosities.
[0013] In one form, the trochanters are supported by: the upper
layer of the first cushion, and the peripheral region of the second
cushion together with the underlying lower portion of the first
cushion.
[0014] In one form, the ischial tuberosities are supported by the
upper layer of the first cushion and the second cushion above the
base of the second cushion.
[0015] In one form, the second cushion lateral sides are contained
within the first cushion.
[0016] In a further broad form, the present invention provides a
seat cushion comprising: a buffer zone of a first foam material; a
support zone of a second foam material; and the support zone is
contained within the buffer zone with a common base; wherein a
peripheral region of the support zone overlays a lower portion of
the buffer zone; and wherein the second foam material is stiffer
than the first foam material.
[0017] In a further broad form, the present invention provides an
internal support system for a cushion, mattress or the like, for
supporting the body of a user, the internal support system
including: a main portion having a body facing side that
substantially opposes a base side; and a support portion located at
least partly within the main portion, the support portion including
a core portion and at least one peripheral portion which extends
laterally from the core portion, wherein the height of the core
portion is greater than the height of the at least one peripheral
portion, the height being that as determined in the direction from
the base side to the body facing side of the main portion, wherein
the support portion is more resistant to deformation than the main
portion.
[0018] In one form, at least part of the core portion forms part of
a base periphery of the internal support system.
[0019] In one form, the support portion is located such that part
of the main portion separates the support portion and the body
facing side of the main portion.
[0020] In one form, the proportion of support portion between the
body facing side and the base side of the main body portion
decreases from the core portion to the at least one peripheral
portion such that the internal support system provides a varying
support profile.
[0021] In one form, the least one peripheral portion tapers in an
outward lateral direction.
[0022] In one form, the support portion includes a base surface and
a top surface, the base and top surfaces being substantially
parallel in the core portion, and, at least a portion of the base
surface sloping toward the top surface to provide the one or more
peripheral portions.
[0023] In one form, part of the main portion separates the at least
one peripheral portion from the base side of the main portion.
[0024] In one form, the support portion is removably located within
the main body portion. In one form, the support portion is
slidingly received by the main portion.
[0025] In a further broad form, the present invention provide an
internal support system for a cushion, mattress or the like, for
supporting the body of a user, the internal support system
including: a main portion; and a support portion located at least
partly within the main portion, the support portion being more
resistant to deformation than the main portion, wherein the
proportions of support portion and main portion vary laterally
through the internal support system to provide a varying support
profile.
[0026] In a further broad form, the present invention provides a
cushion including an internal support system as described in any
one of the above forms.
[0027] In a further broad form, the present invention provides a
mattress including an internal support system as described in any
one of the above forms.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] The description is made with reference to the accompanying
drawings, of which:
[0029] FIG. 1 is a schematic of a side sectional view of a prior
art foam cushion block;
[0030] FIG. 2 is the prior art foam cushion of FIG. 1 being sat
upon by a seat user;
[0031] FIG. 3 is a side sectional schematic of a prior art foam and
spring seat being sat upon by a user;
[0032] FIG. 4 is a side sectional schematic of a prior art webbing
based seat, also being sat upon by a user;
[0033] FIG. 5 is a schematic of a plan view from the top or seating
surface of a seat cushion according to one example of the
invention;
[0034] FIG. 6 is a schematic of a perspective view of the seat
cushion of FIG. 5, also viewed mainly to the upper seating
surface;
[0035] FIG. 7 is a schematic of a sectional view along the lines
7-7 in FIGS. 5 and 6;
[0036] FIG. 8 is the sectional view of FIG. 7 with the user sitting
on the seat cushion;
[0037] FIG. 9 is a schematic of a sectional view along the lines
9-9 in FIGS. 5 and 6;
[0038] FIG. 10 is a sectional view like FIG. 7 along the lines 7-7
in FIGS. 5 and 6, showing a number of example, preferred
dimensions;
[0039] FIGS. 11 and 12 are schematics to respective plan, upper and
side sectional technical drawing views of a first cushion or a
containment zone of the seat cushion;
[0040] FIGS. 13 and 14 are schematics to respective base plan and
side elevational technical drawing views of a second cushion insert
or support zone for the first cushion of FIGS. 11 and 12;
[0041] FIGS. 15 and 16 are schematics to respective plan, upper and
side sectional technical drawing views of a complete seat cushion
with alternative dimensions and styling to the seat cushion
components shown in FIGS. 11 to 14;
[0042] FIG. 17 is a rear perspective view of one example of seat
cushion according to the invention;
[0043] FIG. 18 is rear perspective view of a further example of a
seat cushion according to the invention, in a flipped position,
with base upward facing;
[0044] FIG. 19 is rear perspective view of a further example of a
seat cushion according to the invention, in a flipped position,
with base upward facing, showing insertion/removal of second
cushion/support zone; and
[0045] FIG. 20 shows a perspective view of a mattress having an
internal support system according to one example of the
invention.
DETAILED DESCRIPTION
[0046] Embodiments of the invention provide an internal/integral
support system that can be implemented in cushions, mattress and
the like, for supporting the body of a user.
[0047] One preferred form of the invention is embodied as a seat
cushion. Prior art seats such as described with respect to prior
art FIGS. 1 to 4 suffer from a lack of a way to re-distribute
forces more satisfactorily and comfortably across the buttocks, and
reduce the forces and pressures on the ischial tuberosities
(sitting bones) 216 areas of the buttocks 212. In addition, those
prior art seats which may seek to re-distribute undue pressure from
the ischial tuberosities by softer and deeper cushions and/gel pads
often fail to provide sufficient suspension of the trochanters 218.
Instead such prior art seating may provide an uncomfortable and
restrictive sideways force 414 to the buttocks 212 and the
trochanters 218.
[0048] FIG. 5 is a plan view from the top or seating surface of a
seat cushion 510 of the invention. FIG. 6 is a perspective view of
the seat cushion 510 of FIG. 5, also viewed mainly to the upper
seating surface. The seat cushion 510 is a composite or hybrid
cushion with a first cushion 512 and a second cushion 514. The
first cushion 512 forms the overall shape of the seat cushion 510
and features a front edge 516, a rear edge 518 as well as left and
right sides 520. The second cushion 514 is an insert to the first
cushion 512. In FIGS. 5 and 6 an outline of the second cushion
insert 514 is shown by dashed lines within the first cushion
512.
[0049] FIG. 7 is a sectional view along the lines 7-7 in FIGS. 5
and 6. The second cushion 514 is shown contained within the first
cushion 512 with a common base 710. That is a base surface 712 of
the second cushion 514 is substantially on the same corresponding
level as the common base 710 shown in FIG. 7. The second cushion
514 has an approximately trapezoidal cross-sectional shape with a
top surface 714, a substantially parallel bottom surface 712 and
sloping lateral sides 716. The top surface 714 of the second
cushion underlays an upper layer 718 of the first cushion 512.
[0050] The top surface 714 area of the second cushion 514 is
greater than that of the base surface 712 area so that the lateral
sides 716 of the second cushion 514 overlay a lower portion 720 of
the first cushion 512. The overlaid lower portion 720 of the first
cushion 512 is shown generally in dashed line outline in FIG. 7.
Accordingly a peripheral region of the second cushion is defined or
formed by portions of the second cushion 514 above the lateral
sides 716 which overlay the lower portions 720 of the first cushion
512 that are adjacent and may surround the base 712 of the second
cushion. In other words, the second cushion has a top surface with
an area greater than an area of the base of the second cushion to
form a peripheral region of the second cushion that overlays a
lower portion of the first cushion.
[0051] In FIG. 7 the trochanters or femur heads 218 are shown
substantially above the peripheral region 716, 720 of the varying
composite region of the first and second cushions 512, 514. The
ischial tuberosities or sitting bones 216 are shown substantially
above the base surface 712 of the second cushion 514. Accordingly
when the user 210 sits, as described with respect to FIG. 8 below,
the ischial tuberosities 216 may be supported by the full thickness
of the second cushion 514 together with the upper layer 718 of the
first cushion 512. Whilst the trochanters 218 are supported by the
peripheral region 716, 720.
[0052] The first cushion material stiffness or hardness may be
selected to be of less than a stiffness or hardness of a material
selected for the second cushion. That is the first cushion material
is softer than the second cushion material. The importance of the
second cushion material being stiffer or harder than the first
cushion material is described below with respect to FIG. 8. The
first and second cushion materials may be of a suitable foam, for
example a polyurethane foam may be used where the reactants of
diisocynate and polyol are varied with respect to their speed of
reaction in order to vary the properties of support, stiffness and
recovery as desired. The composition of the second foam material
for the second cushion may also be formulated by a person skilled
in the art to vary the shear performance of the foam. For example
to the performance of the lateral movement of the second cushion
514 into the surrounding lower portions 720 of the first cushion
512 as described below.
[0053] The foam material or "first foam material" for the first
cushion may also be formulated to have a memory foam effect. Memory
foam is still an elastic foam, however it has a delayed time to
recover its original shape after compression. The use of memory
foam is beneficial for conforming to the shape of the buttocks 212.
A suitable memory foam may be formulated by a person skilled in the
art. For example a selected blend of a polyurethane and gel
compounds may provide the desired memory effect, stiffness, heat
conductivity and/or breathability. The selection of heat
conductivity and breathability for the memory foam may be important
to reduce body heat build-up in the first cushion upper layer
718.
[0054] In one example for a user of approximately <75 kg weight
the hardness of the second cushion or insert 514 may be
approximately 32 points with an approximate range of 29 to 35
points. Where the hardness measurement is by a common industry
technique of an Asker X Durometer, www.asker.co.jp. For foam
materials, the durometer has a type F flat, disc shaped measurement
probe or indenter. The measurement scale is a 100 point calibrated
scale suitable for measurements of materials such as urethane foam,
polystyrene foam and sponges. For example 0 point is no resistance
whilst 100 points is a comparatively unyielding surface for these
types of foam or sponge like materials. The hardness of the first
cushion 512 for a user of approximately <75 kg weight may be
less at approximately 27 points with an approximate range of 24 to
28 points.
[0055] In another example for a user >75 kg the hardness or
stiffness of the second cushion 514 may be approximately 36 points
with a range of 33 to 39 points. For the first cushion 512 the
hardness or stiffness may be less at approximately 27 points with a
range of 24 to 30 points.
[0056] The desired foam stiffness or hardness for each cushion 512,
514 may also be expressed as a range of the ratios of the hardness
values from an Asker Durometer measurement. The preferred ratio
range for the hardness ratio of the second cushion 514 to the first
cushion from the above example is approximately 1.19 to 1.33 for
weights above and below 75 kg. For a weight of <75 kg the ratio
may be up to approximately 1.46 whilst for a weight of >75 kg
the ratio may be up to approximately 1.63.
[0057] The foam material stiffness values for the first and second
cushion materials may also be selected by a person skilled in the
art so that the invention performs as described below with respect
to FIG. 8. For example the difference in foam stiffness values are
not so great that the lateral sides 716 of the second cushion 514
in the peripheral region do not fold over, sandwich or collapse the
lower portions 720 of the surrounding first cushion 512.
[0058] FIG. 8 is the sectional view of FIG. 7 with the user 210
sitting on the seat cushion 510. The softer upper layer 718 of the
first cushion 514 is comparatively readily compressed by the user's
buttocks 212, as shown for example in FIG. 8. The stiffer or harder
material of the second cushion 516 provides more support for the
ischial tuberosities 216 and is compressed less than the softer
material of the first cushion 514. In FIG. 8 dashed lines 810 are
used to show the original position of the lateral sides 716 of the
second cushion 514. The lateral sides 716 have been displaced
outwards 812 into the lower portion 720 of the surrounding first
cushion 512. At least two beneficial effects result from this
action.
[0059] The first beneficial effect is that the compression of the
second cushion by the ischial tuberosities is also dependent on the
stiffness of the first cushion material surrounding the second
cushion. In typical practice the thickness of the second cushion
and the stiffness of the second cushion material prevent the
vertical bottoming out of the ischial tuberosities to the base 712
of the second cushion. The new and inventive use of the sloping,
lateral sides 716 to the second cushion allow the second cushion to
displace into the softer first cushion 512 laterally and downwardly
as shown by the arrows 814. This displacement allows for the
effective lateral stiffness of the second cushion to be less than
downward stiffness used to support the ischial tuberosities and
prevent bottoming out to the base 712. Accordingly the second
cushion 514 to the sides at least of the ischial tuberosities is
softer and more comfortable. The softer first cushion material
surrounding the harder second cushion material at the sloping
lateral sides 716 prevents the collapse of the sides 716 and
maintains adequate support through to the common base 710 of the
seat cushion 510. In other words the first cushion 512, 720
material surrounding the second cushion 514 acts to contain and
support the second cushion.
[0060] The second beneficial effect results from the peripheral
region's varying composite stiffness. The composite stiffness or
hardness in the peripheral region is made up of the second cushion
at the lateral and sloping sides 716 overlaying the lower portions
720 of the first cushion 512 adjacent and/or surrounding the second
cushion 514. The composite stiffness of the peripheral region 716,
720 varies with horizontal distance outwards from a center of the
second cushion as shown by a center line and arrow 816. The
stiffness presented to the compressing buttocks by the seat cushion
510 varies from being dominated by the material of the second
cushion at and adjacent the center 816 in order to support the
ischial tuberosities. Then gradually decreasing with distance
towards where the lateral sides 716 of the second cushion 514
intersect with the common base 710. Further outwards from the
center 816, in the peripheral region 716, 720 the stiffness
presented by the seat cushion 510 is a composite of the peripheral
region 716, 720 of the second cushion 514 and the lower portions
720 of the first cushion 512. The stiffness of the peripheral
region 716, 720 becoming closer to the surrounding first cushion
material stiffness with increasing horizontal distance from the
second cushion center 816. Beyond the peripheral region the
stiffness of the seat cushion 510 is dominated by the first cushion
material.
[0061] The varying or gradient of composite stiffness in the
peripheral region 716, 720 allows the seat cushion to support the
buttocks about the trochanters but not with a sideways force 414
applied to the buttock sides typical in the prior art. That is the
sideways force 414 described above with respect to the prior art
FIGS. 1 to 4 is absent or substantially reduced. In other words the
trochanters can remain comfortably suspended with no or minimal
sideways force to the buttocks adjacent the trochanters resulting
from sinking into the seat cushion too far.
[0062] A combined beneficial effect is also obtained from: the
second cushion's displacement of the lateral side 716 into the
lower portion 720 of the surrounding first cushion 510 together
with the varying composite stiffness of the peripheral region.
Heavier users may cause the second cushion to compress more and
laterally displace into the lower portions 720 of the first cushion
at the lateral sides 716. With increased displacement of the
lateral walls 716 into the lower portions 720 the composite
stiffness may increase within the peripheral region. Accordingly
for heavier users more support is supplied to the buttocks adjacent
the trochanters 218 so as to provide adequate suspension of the
trochanters and minimise the undesirable sideways force of the
first cushion's seating surface against the side of the buttocks
212. Thus the seat cushion 510 adapts the support to a user across
the ischial tuberosities to the trochanters according to the weight
of the user so that the trochanters are appropriately supported and
suspended without an undue sideways force applied to the buttocks
adjacent the trochanters.
[0063] From the descriptions with respect to FIGS. 7 and 8 it will
be readily appreciated that the lateral sides 716 of the second
cushion 514 are always contained in the first cushion 512. In
particular the lateral sides 716 are contained with the surrounding
and/or adjacent lower portions 720 of the first cushion 512.
[0064] It will be readily appreciated that adjusting the relative
and absolute values for the stiffness (or hardness) of the
materials making up the first and second cushions 512, 514 may be
used to improve the performance of the seat cushion to lighter and
heavy users compared with the bulk of the user population. A memory
foam material may also be used within the first cushion 512 to
allow the seat cushion to mould further to the user with prolonged
use. For example the memory foam may relax or distort further with
body heat and prolonged use to provide more conformal support to
the user as well as a beneficial variation in support with
prolonged, continuous use. In particular the use of memory foam in
the first cushion may vary the support provided to the lateral
sides 716 provided by the surrounding lower portion 720 of the
first cushion 512.
[0065] The invention described with respect to FIGS. 5 to 8 may
also be described as having a support zone 514 corresponding to the
second cushion 514. The support zone 514 is surrounded by a
containment or buffer zone 512 corresponding to the first cushion
512 and in particular the lower portions 720 of the first cushion.
The support zone 514 material has a higher stiffness or resistance
to compression than the material used for the buffer or containment
zone 512. For example a high density polyurethane foam, without any
memory performance, may be selected depending on a user's weight.
Higher density polyurethane foam for heavier users and lower
density foam for lighter users. When the user sits upon the support
zone 514 the higher stiffness or resistance of the support zone is
provided through to the base 712. In addition the support zone
disperses or laterally transfers the user's weight load to the
adjoining containment or buffer zone 512, 720 that has a softer and
less resistant material than that for the support zone. The result
of this lateral transfer of weight is controlled and supported
distribution of the user's weight to the containment/buffer zone to
provide less resistance or stiffness about the ischial tuberosities
but still preventing "bottoming out" of the ischial tuberosities to
the seat cushion base 710, 712.
[0066] That is the seat cushion distributes the user's weight
across two zones. The support zone 516 for the ischial tuberosities
(sitting bones) and the buffer zone 512, 720 for the trochanters.
This approach allows for 97% of trochanter widths and 97% of the
ischial tuberosity widths for the adult population to be
accommodated by a single seat cushion size. The scaling of the seat
cushion 510 to the pelvic and femur skeletal anatomy is described
further below with respect to FIG. 10. In addition the use of the
support zone 514 with the buffer zone 512, 720 allows for greater
weight ranges to be accommodated due to the composite mix of
stiffness between the support zone 514 and the buffer zone 512, 720
as well as the structure and operation of the support zone with the
buffer or containment zone.
[0067] It will be readily appreciated that the upper layer 718 of
the first cushion to the second cushion or support zone 514 is
optional for the seat cushion 510. The upper layer 718 may improve
the seat cushion integrity and comfort but it is optional to the
performance of the invention as described herein.
[0068] FIG. 9 is a sectional view along the lines 9-9 in FIGS. 5
and 6. FIG. 9 is the orthogonal sectional view to FIG. 7. The
sectioned second cushion 514 insert in the first cushion 512 shown
in FIG. 9 is also approximately a trapezoidal cross-sectional shape
with the same top surface 714 and base surface 712 as shown in FIG.
7. The cross-sectional trapezoidal shape has a sloping front side
910 and a sloping rear side 912. In FIG. 9 an angle between the
sloping front and rear sides 910, 912 and the common base 710 is
approximately 60.degree.. Whilst in FIG. 7 the sloping lateral
sides 716 are at an approximate angle of 45.degree. to the common
base 710. The peripheral region 716, 720 of the left and right hand
lateral sides 716 of the second cushion 514 shown in FIG. 7 are to
accommodate a variation in the spans between the trochanters 218
for a substantial proportion of the adult user population.
Accordingly a shallower or more acute angle of 45.degree. may be
used for the lateral side peripheral region 716, 720 in order to
have an appropriately wide composite stiffness region in the
periphery to support and suspend the trochanters 218. For the front
and rear peripheral regions 910, 912 a greater angle may be used to
provide a horizontally narrower peripheral region. A narrower front
peripheral region 910 may be desirable to transition more rapidly
from the harder support zone second cushion 514 to the softer
buffer zone first cushion for the comfort and angling down of the
user's thighs. A narrower rear peripheral region 912 may be used to
provide a transition to the softer first cushion 512 for the
increased comfort of user's sacrum (tail bone).
[0069] It will be readily appreciated that the 60.degree. angle for
the front and rear sides 910, 912 may be varied to suit what the
desired peripheral region width is required and comfortable for a
seat cushion user population. The variation of the 45.degree. angle
for the lateral side 716 peripheral region is detailed further with
respect to FIGS. 10 to 16.
[0070] The insert second cushion 514 and support zone which has
been described herein has been to a trapezoidal cross-section with
a larger rectangular top surface 714 area compared with the smaller
base surface 712 area of a square shape as shown in the FIGURES.
However it will be readily appreciated that to provide the
peripheral region of composite stiffness in the seat cushion 510
that other shapes for the second cushion 514 may be used. For
example the top and bottom surfaces may be circular so that the
shape formed is a frustum with the larger flat surface being
uppermost in order to form the sloping sides and peripheral region.
The peripheral region would then be a peripheral annular region
about the frustum. In another variation the top and bottom surfaces
may be ellipsoidal. In a further variation the sloping sides to the
front and rear of the second cushion may be absent, the support
zone 514 and peripheral region 716, 720 only being provided for the
trochanters 218.
[0071] FIG. 10 is a sectional view like FIG. 7 along the lines 7-7
in FIGS. 5 and 6. FIG. 10 additionally shows a number of example,
preferred dimensions found by the inventor and derived from
anthropometric data as described below. These preferred dimensions
for the user 210 and the seat cushion 510 may be used to scale the
skeletal anatomical features anthropometric values of a population
of users to the features and functions of the seat cushion 510. For
the users a span 1010 mm between the outer extent of the heads of
the femurs or trochanters 218 has been found to be a preferred
dimension. The span or width 1010 mm across the trochanters 218 may
also be referred to as the skeletal width. Another preferred
anthropometric measurement is a span or width 1012 mm across the
sitting bones or ischial tuberosities 216. The width 1012 mm
between the ischial tuberosities may be determined between the
outermost projections that can easily be felt or otherwise suitably
measured.
[0072] It has been found by the inventor that a 97 percentile of
the trochanter width 1010 mm for an adult user population may be
used to set a width 1014 mm of the top surface 714 of the second
cushion 514. If the width 1014 mm of the top surface 714 is made
approximately the same as the 97 percentile trochanter width 1010
mm, then the inventor has found that approximately 97% of the adult
population will have their trochanters 218 adequately supported and
suspended by the peripheral region 716, 720.
[0073] It has also been found by the inventor that a 97 percentile
ischial tuberosities width 1012 mm may be used to derive a width
1016 mm of the base 712 of the second cushion support zone 514. If
the base width 1016 is made approximately the same as: the ischial
tuberosities width 1012 mm plus at least approximately 30 mm, then
the inventor has also found that approximately 97% of the adult
user population ischial tuberosities' 216 are supported adequately
and comfortably. It will be readily appreciated that the 97
percentile adult population anthropometric values may vary with
user population location. For example different 97 percentile
values may be used for the different user populations in each of
Europe, Northern America and Japan.
[0074] FIGS. 11 to 16 are technical drawings of various views of
the first and second cushions 512, 514 of the seat cushion 510. The
drawings are to a pre-production seat cushion 510. The dimensions
and angles shown in FIGS. 11 to 16 are to suit a 97% percentile
adult population. FIG. 11 is a plan, elevational view of the seat
cushion from the seating surface. FIG. 12 is a cross-sectional view
along the line 12-12 shown in FIG. 11. FIG. 12 shows the cutting
1210 made into the first cushion 512 to provide a cavity 1210 for
the second cushion material. The second foam material of the second
cushion material may be blow moulded into the cavity 1210 and set.
During the blow moulding into the cavity 1210, the first and second
cushion materials may be bonded together. The bonding may be done
so as to be un-noticeable to the user whilst allowing the seat
cushion 510 to perform as described herein. In FIG. 12 an alternate
angle of 39.56.degree. is shown for the front side 910 to the
common base 710 angle described with respect to FIG. 9.
[0075] FIGS. 13 and 14 are respective base plan and side
elevational views of the second cushion 514 insert corresponding to
FIGS. 11 and 12. An alternate angle of approximately 36.degree. for
the lateral side 716 to the common base 710 may be derived from the
drawing dimensions. This is an alternate angle to the 45.degree.
value described with respect to FIGS. 7 and 9.
[0076] FIGS. 15 and 16 are respective plan, upper and side
sectional views of a complete seat cushion 510 with some
alternative dimensions and styling to the seat cushion components
shown in FIGS. 11 to 14.
[0077] The seat cushion 510 described herein has a further
advantage to providing support to the user with reclining angle.
For example the seat cushion provides support as described herein
for a reclining angle range of at least 90.degree. to 105.degree.
for an angle defined by the user's back to the horizontal plane
through the buttocks 212 and upper thighs of the user.
[0078] Further example embodiments of seat cushions according to
the invention are shown in FIGS. 17 to 19. In these examples,
rather than have the second cushion/support zone inserted into a
cavity formed in the base of the first cushion, the second
cushion/support zone is inserted into the rear wall of the first
cushion/buffer zone. This provides that, the second cushion/support
zone may be interchanged when the chair/seat (into which second
cushion/support zone is incorporated) is fully assembled.
[0079] For example, FIG. 17 shows a rear view of a seat cushion
1700, having a second cushion/support zone 1714 fully inserted
within a first cushion/buffer zone 1712. As shown, whilst the
second cushion still has a substantially trapezoidal cross section,
the rear portion 1713 thereof does not include a sloped/tapered
peripheral portion. Rather the rear portion 1713 thereof is shaped
to align substantially flush with the rear surface 1715 of the
first cushion 1712. The remaining periphery regions 1716 are,
however, still sloped/tapered, as per the embodiments of FIGS. 5 to
15, so as to provide the beneficial effects of the invention as
described above.
[0080] FIG. 18 shows a rear underside perspective view of a
slightly modified version of the seat cushion of FIG. 17. In FIG.
18, the cavity that receives the second cushion 1814 is not
open/exposed at the underside of the first cushion 1812. Rather,
the second cushion 1814 forms a tongue to be received in a slot of
the first cushion 1814. FIG. 19 on the other hand, illustrates an
embodiment wherein the cavity for the receiving the first cushion
1912 is substantially open/exposed at the underside. As shown in
FIG. 19, the second cushion 1914 is slidingly received with the
first cushion 1912. In the embodiment of FIG. 19, the periphery
regions 1916 engage with corresponding grooves in the first cushion
to substantially prohibit release therefrom by means other than out
through the rear of the first cushion 1912.
[0081] It will be appreciated that in the forms as shown in FIGS.
17 to 19, the rear portions of second cushions (e.g. 1714, 1814,
1914) are shaped to be substantially flush with the rear surface of
the first cushion (e.g. 1712, 1812, 1912), rather than being
sloped/ramped.
[0082] It will be readily appreciated that the seat cushions as
described herein may be used in the office, factory or aged care
environments. The seat cushions may also be applied to lounge and
dining seating, wheelchairs, car and truck seats. The seat cushions
as described herein may also be retrofitted to an existing
structure of a seat or chair. Alternatively, the seat cushions may
be in a portable cushion form for using on existing seating
surfaces.
[0083] It will also be appreciated that the first and second
cushions (or support and buffer zones) may be formed of any
suitable cushioning/support material (i.e. materials other than
foam, such as, for example, gel, rubber or polymer based
materials).
[0084] Whilst the above described forms of the invention are
embodied as seat cushions, typically for use in office chairs or
the like, it will be appreciated that other forms may be embodied
more generally for other supportive type furniture, such as, for
example, bed mattresses (see for example FIG. 20). Broadly
speaking, the invention may be described as an internal support
system for cushions, mattresses or the like, that are generally
used for supporting the body of a user. The internal support system
generally including a main portion and a support portion located at
least partly within the main portion. Typically, the support
portion is more resistant to deformation/compression than the main
portion (although in alternate forms the opposite may be true), and
the proportions of support portion and main portion vary laterally
through the internal support system to provide a varying support
profile.
[0085] For example, an internal support system (e.g. embodied in a
cushion or mattress etc.) may have a main portion with a body
facing side substantially opposing a base side. A support portion
may be located at least party within the main portion, that
includes a core portion and at least one peripheral portion which
extends laterally therefrom. The height of the core portion may be
greater than the height of the at least one peripheral portion so
as to provide the varying support profile (the height being that as
determined in the direction from the base side to the body facing
side of the main portion). Generally, the support portion is more
resistant to compression/deformation than the main portion, and may
be removably located therein.
[0086] It will be appreciated that the shape of the support portion
may affect the support/cushioning profile. In one example, the
support portion may include a base surface and a top surface, the
base and top surfaces being substantially parallel in the core
portion, and, at least a portion of the base surface sloping toward
the top surface to provide the one or more peripheral portions.
[0087] Location of the support portion within the main portion may
vary too, and may impact the support/cushioning profile. Generally,
at least part of the core portion forms part of a base periphery of
the internal support system. The support portion may also be
located such that part of the main portion separates the support
portion and the body facing side of the main portion. Part of the
main portion may also separate the at least one peripheral portion
from the base side of the main portion.
[0088] The peripheral portion(s) of the support portions too may
take a variety of forms, but are typically tapered or ramped, such
that the height thereof gradually reduces in the outward lateral
direction. As the height reduces, a larger proportion of the
support/cushioning profile of the internal support system is
provided by the main portion. As such, it will be appreciated that
in some forms, the area of the peripheral portions may have graded
support profile.
[0089] It will also be appreciated that by altering the material
selected for the main and support portions, the support/cushioning
profile can be varied. For example, materials of varying
compressibility, resilience, hardness, stiffness etc. may be
selected to vary the support/cushioning profile. In one example,
the materials selected are foam rubber materials or have foam
rubber like properties i.e. are resiliently deformable/compressible
so as to provide cushioning.
[0090] It is thus apparent that the internal support system as
described herein may be used to address adverse effects on the body
at high pressure areas created during extended sitting or lying
(e.g. at the trochanters, iscial tuberosities and pelvis).
[0091] In this specification, terms denoting direction, such as
vertical, up, down, left, right etc. or rotation, should be taken
to refer to the directions or rotations relative to the
corresponding drawing rather than to absolute directions or
rotations unless the context require otherwise.
[0092] Although the invention has been herein shown and described
in what is conceived to be the most practical and preferred
embodiments, it is recognized that departures can be made within
the scope of the invention, which are not to be limited to the
details described herein but are to be accorded the full scope of
the appended claims so as to embrace any and all equivalent
assemblies, devices, apparatus, articles, compositions, methods,
processes and techniques.
[0093] In this specification, the word "comprising" is to be
understood in its "open" sense, that is, in the sense of
"including", and thus not limited to its "closed" sense, that is
the sense of "consisting only of". A corresponding meaning is to be
attributed to the corresponding words "comprise, comprised and
comprises" where they appear.
[0094] It will further be understood that any reference herein to
known prior art does not, unless the contrary indication appears,
constitute an admission that such prior art is commonly known by
those skilled in the art to which the invention relates.
* * * * *
References